Usage of the Internet has increased dramatically in the last few years. Most users of the Internet access Web pages that are stored at Web sites. The Web pages are typically hypertext documents that are downloaded from an Internet server to a client computer system. These hypertext documents are encoded in the hypertext markup language (HTML). HTML is a simple markup language that enables the development of hypertext documents that are platform independent. HTML documents follow a particular syntax. An example document is helpful to illustrate this syntax:
<!DOCTYPE HTML PUBLIC “-//IETF//DTD HTML 2.0//EN”>< HTML><!-- Here's a good place to put a comment. --><HEAD><TITLE>Structural Example</TITLE></HEAD><BODY><H1>FirstHeader</H1><P>This is a paragraph in the example HTML file. Keep in mindthat the title does not appear in the document text, but thatthe header (defined by H1) does.</P><OL><L1>First item in an ordered list.<L1>Second item in an ordered list.<UL COMPACT><LI> Note that lists can be nested;<LI> Whitespace may be used to assist in reading theHTML source.</UL><LI>Third item in an ordered list.</OL><P>This is an additional paragraph. Technically, end tags arenot required for paragraphs, although they are allowed. You caninclude character highlighting in a paragraph. <EM>This sentenceof the paragraph is emphasized.</EM> Note that the &15;/P&gt;end tag has been omitted.<P><IMG SRC =“triangle.xbm” alt=“Warning: ”>Be sure to read these <b>bold instructions</b>.</BODY></HTML>
As can be seen in the above example, hypertext documents typically contain a number of tags. The tags are delimited by “<” and “>.” Tags delimit elements such as headings, paragraphs, lists, character highlighting, and links. Most HTML elements are identified in the document by a start tag, which gives the element name and attributes, followed by the content that, in turn, is followed by an end tag. Start tags are delimited by “<” and “>,” whereas end tags are delimited by “</” and “>.” An example of a start tag in the above example document is “<H1>” and an example of an end tag is “</H1>.” In the above example document, the tags are used to delimit lists, paragraphs, the head of the document, and the body of the document.
One of the elements that may be included in a document written in HTML is a hyperlink or link. A hyperlink enables the user to gain access to another Web site by activating the hyperlink. Each hyperlink includes an anchor and a URL. The anchor specifies the text or other content that will be displayed to a user when the hypertext document is displayed on the user's computer. The anchor may include text or graphics. The URL is a uniform resource locator that specifies the location of the associated Web site or Internet resource. An example of a URL is http://www.msn.com.
When a hypertext document is rendered on a user's computer, the hypertext document may include a number of hyperlinks. A user utilizes the hyperlink by positioning a mouse cursor to point within a hot region associated with the anchor and clicking a mouse button. The Web browser translates this action into a request to gain access to the resource specified by the URL contained within the hyperlink. In the simplest case, the hyperlink appears to the user as text that is differentiated from other text by being highlighted, boldfaced, or distinctly colored. The hyperlink, however, may also appear to the user as a graphical image. The hot region or the hyperlink may encompass the image. In such a case, if the user positions the mouse cursor to point within the hot region and clicks the mouse, the resource associated with the URL contained in the hyperlink will be accessed. In the most complex case, the hyperlink is contained within an image map. An image map is a construct that represents a set of hyperlinks. The image may appear as an image that is segmented into respective hot regions that are associated with respective hyperlinks. Thus, when the user positions the mouse cursor to point inside a given hot region that is part of an image map and clicks the mouse button, the resource identified by the URL for the associated hyperlink is accessed.
One of the difficulties with such hyperlinks is that they are often difficult to discover. Sometimes the visual cues for delineating hyperlinks within a hypertext document are not very effective. This problem is especially acute with image maps where it is difficult to discern the boundaries of the respective hot regions. Typically, a user is able to identify the presence of hyperlinks by moving the mouse cursor throughout the body of the document and noticing when the mouse cursor changes form. In at least one conventional system, the mouse cursor changes from an arrow to a hand when the hot region of a hyperlink is encountered. One limitation of this approach is that a user must navigate the entire document in order to be certain that he/she has located each hyperlink within the document in order to be certain that he/she has located each hyperlink within the document. In addition, a user may not know the extent of the hot region and which hyperlink is associated with a given portion of the screen. Furthermore, users who have difficulty using a mouse, such as handicapped users, cannot readily discern the location of the hot regions for the hyperlinks.